The present invention relates to peer-to-peer networks and, more particularly, but not exclusively, to a battery operated device communicating over a peer-to-peer network.
A communication network includes a transmission and switching fabric that connects a plurality of terminal devices. In a conventional network the intelligence of the network resides within the switching system, which keeps track of all the terminal devices and their addressing. In a peer-to-peer network the network intelligence is distributed among the terminal devices. Each terminal device must publicize its presence and addressing information to its peers of choice and keep track of the presence and addressing of the peers with which it may communicate.
Similarly, three types of application topologies can be defined: mainframe, client-server and peer-to-peer. In a mainframe topology the application is executed by the mainframe and the terminal devices are passive. In a client-server topology a part of the application is executed by the server, and another part is executed by the terminal devices. In a peer-to-peer topology almost all of the application is processed by the terminal devices and a server is commonly available for limited coordination functions.
There is a place for all types of networks and application topologies and each has its advantages and disadvantages. Generally, centralized networks are more robust but distributed networks are faster to establish and to develop. The main advantage of peer-to-peer networks and applications is that they can be established by users, at relatively low cost. While most of the networks are still conventional, peer-to-peer networks are becoming increasingly prevalent. Furthermore, a growing number of services are available only via peer-to-peer networks.
In an increasingly mobile society, cellular handset and other mobile communication devices offer a user the ability to be in contact with others or reachable at all times. Wireless networks, such as cellular networks, are usually conventional networks. However, mobile wireless devices should be capable of communicating over peer-to-peer networks as well.
One problem with mobile wireless devices communicating over peer-to-peer networks is the requirement that the peer device continuously present itself and interrogate the presence of its peers. For a battery-powered device this is a problem, because these operations quickly drain the battery. This frequent communication loads the wireless network and may be costly.
Furthermore, wireless devices tend to lose their radio connection with the network due to electromagnetic screening. This phenomenon is common in basements, tunnels, buildings with metal frames, etc. This not only prevents real-time communication but also adversely affects non-real-time communication, such as messaging, including immediate messaging services, short messaging services, etc., when provided over a peer-to-peer network.
When connecting two or more conventional networks, it is the responsibility of the networks to bridge differences of standards, formats and capabilities between the networks, and to make these differences transparent to the terminal devices. This functionality is usually provided by a bridge or a gateway device that is positioned between the networks to provide conversion services. This is obviously impossible when peer-to-peer networks are involved. A terminal device operating in two or more peer-to-peer networks must be equipped to support the specifications of each of the networks. However, when a peer-to-peer network spans two or more ‘physical’ networks, such as a fixed network and a wireless network, the requirements of the peer-to-peer network may be incompatible with one of the physical networks, typically being the cellular network.
There is thus a widely recognized need for, and it would be highly advantageous to have, a peer-to-peer network, and peer-to-peer devices, devoid of the above limitations.